Abstract 144

Background. Treated HPA children show low blood cholesterol (C) levels. Aim. To investigate the genetic influence on the blood lipid profile of HPA. Subjects and methods. 35 HPA children on diet (21 M, 14 F, aged 2-12 years) with the six most frequent phenylalanine-hydroxylase (PAH) deficiency mutations in Italy were investigated for the lipid profile, including the medians (mmol/L) of total-C (TC), HDL-C (enzymatic methods) and LDL-C (Friedewald formula) of the 6-monthly controls after the 1st year. ApoE and ApoB polimorphisms were investigated with restriction-enzyme analysis. Diets were assessed by repeated 24-hour recalls. Statistics: non-parametric tests, chi square and Fisher's exact test. Results. HPA subgroups were similar for low total fat and saturated fat intakes. Subjects with either Y414C or L48S mutations (n=13) showed higher median blood TC (3.83 vs 3.36, P=0.009) and LDL-C (2.22 vs 1.83, P=0.03) than HPA (n=22) with IVS10nt546, R158Q, R261Q or P281L. A trend towards between-group differences in ApoB (but not ApoE) polimorphism was present too. Conclusions. Genetic variables may further explain the low blood cholesterol levels in treated HPA.